[pkg-gnupg-maint] Bug#643341: Bug#643341: Bug#643341: libgpg-error-dev: cross-compiling anything based on libgpg-error is painful

[Simon McVittie]

On Wed, 17 Oct 2018 at 14:31:50 +0900, NIIBE Yutaka wrote:
> At configure time, if it detects libdir for multiarch, it lets
> gpg-error-config script architecture independent to dynamically define
> PKG_CONFIG_LIBDIR (by CC or gcc -dumpmachine).

The multiarch tuple used to form ${libdir} on Debian is not always
identical to the GNU host. On some architectures (mainly i386 and the
32-bit ARM family) it's a normalized form of the GNU host, using the
oldest or most generic compatible CPU: for instance Debian i386:

    % dpkg-architecture -ai386 -qDEB_HOST_MULTIARCH
    i386-linux-gnu

    # in current Debian/Ubuntu (older Debian used i486, i586 here)
    # same as gcc -dumpmachine
    % dpkg-architecture -ai386 -qDEB_HOST_GNU_TYPE
    i686-linux-gnu

and similarly the multiarch tuple for 32-bit ARM is something like
arm-linux-gnueabi, not armv5tel-linux-gnueabi.

There's a Debian-specific option "gcc -print-multiarch" added by a
Debian patch, although not all of our compilers have a similar patch
(gcc does but clang doesn't).

I think it would probably be better for Debian to patch
src/gpg-error-config-new.in in our version of gpg-error, rather than
trying to solve this generically upstream, because we can make a lot
more assumptions about install paths than you can.

    smcv